AMPHITHERIUM. 55 



The probability entertained in 1838, and supported by 

 the degree of resemblance between AmpJtitherium and Myr- 

 mecobius in the number and form of the molar series of 

 teeth, has since been diminished by the discovery of the 

 right ramus of a lower jaw, presenting its external sur- 

 face to the observer, and the most complete of all the 

 extant specimens of the AmpMtherium : it is figured, of 

 the natural size in outline, and twice the natural size in the 

 finished cut, at the head of the present section (fig. 15). 



This jaw, which is in the choice collection of Professor 

 Buckland, contains the whole series of twelve molar teeth, 

 the last six (m) being quinque-cuspidate; the six anterior 

 ones (p) unicuspidate, with one or two small basal accessory 

 cusps ; it, also, displays the socket of one small canine (?), 

 and three small incisors (i), in situ ; altogether amounting 

 to sixteen teeth on each side of the lower jaw, as indicated 

 by the sockets of the second specimen above described. 

 The convex condyle, the broad and high coronoid process, 

 the projecting angle, the varied kinds and double-rooted 

 implantation of the teeth, all unequivocally displayed in this 

 fossil, establish the conclusions deduced from the foregoing 

 specimens, of the existence of a small insectivorous mammal 

 during the oolitic epoch. 



Here, likewise, was a specimen adapted to afford the 

 much desired test of the form of the angular process of the 

 lower jaw. The inward inflection of this process had been 

 long ago pointed out by Cuvier as a character of the genus 

 Didelphys, and I have established its generality in the 

 entire marsupial series, and pointed out its characteristic 

 modifications in the different genera.* 



Dr. Buckland had transmitted this beautiful specimen to 



* Geological Trans. 2nd Series, vol. vi. p. SO. Art. Marsupialia, Todd's 

 Cyclopaedia. 



